A Meson Converter for Generating Thermal Energy from a Meson Flux

The present disclosure relates to the field of energy converters.

Nuclear processes, such as fusion, are by many predicted to play a central role in the energy generation of the future. One of the challenges of extracting energy from nuclear processes is to utilize the large amount of energy that exists in the form of particle radiation originating from the nuclear reaction.

One group of particles that may be generated from nuclear processes comprise light mesons such as kaons and pions. A problem with these mesons is that one needs to extract energy from them before the decay into muons and neutrinos, which are notoriously hard to utilize. Another problem is to extract the energy from long-lived neutral kaons which pass with no interaction through most materials. At present, the detection of light mesons are sometimes tackled by using large calorimeters, i.e. tanks with various expensive fluids. Albeit being suitable for collecting light mesons in large systems, large calorimeters are impractical for energy extraction at a small or medium scale in power generators.

It is an aim of the present disclosure to provide a meson converter for generating thermal energy from a meson flux that can be used in in a wide range of power generation environments.

A first aspect of the present disclosure provides a meson converter for generating thermal energy from a meson flux, the meson converter comprising, a plurality of absorber layers, and a plurality of heat transport layers, where the plurality of absorber layers and the plurality of heat transport layers are arranged alternately in a stack, where each absorber layer is arranged in contact with at least one heat transport layer, and where any two adjacent layers in the stack have dissimilar densities.

According to an embodiment of the present disclosure each absorber layer have a first density, and each transport layer have a second density being different from the first density.

According to another embodiment of the present disclosure each absorber layer comprises a metal plate of a first type.

According to yet another embodiment of the present disclosure the metal plate of the first type comprises at least 50 wt. % of an element with an atomic number of at least 26.

According to yet another embodiment of the present disclosure the metal plate of the first type comprises at least 50 wt. % lead, preferably at least 99 wt. % lead.

According to yet another embodiment of the present disclosure each heat transport layer comprises a metal plate of a second type with a thermal conductivity that is higher than the thermal conductivity of any one of the absorber layers.

According to yet another embodiment of the present disclosure the metal plate of the second type has a thermal conductivity of at least 200 W/m·K.

According to yet another embodiment of the present disclosure the metal plate of the second type comprises aluminium, gold, copper or silver.

According to yet another embodiment of the present disclosure each heat transport layer comprises a conduit configured to conduct a cooling fluid, preferably water.

According to yet another embodiment of the present disclosure the thickness of the stack is at least 2.7 cm, preferably at least 10.8 cm.

According to yet another embodiment of the present disclosure the meson converter further comprises a chamber for containing and conducting water, where the chamber is connected to one side of the stack.

According to yet another embodiment of the present disclosure the meson converter is planar or curved.

A second aspect of the present disclosure provides use of a meson converter for generating thermal energy from a meson flux.

According to an embodiment of the present disclosure the meson flux comprises a kaon flux.

In the following, general embodiments as well as particular exemplary embodiments of the disclosure will be described. References will be made to the accompanying drawings. It shall be noted, however, that the drawings are exemplary embodiments only, and that other features and embodiments may well be within the scope of the disclosure as claimed. Further, the mentioning of references such as “a” or “an” etc. should not be construed as excluding a plurality, and the term “disclosure” may herein be used interchangeably with the term “invention”.

Unless otherwise defined, all terms of art, notations and other scientific terms or terminology used herein are intended to have the meanings commonly understood by those of skill in the art to which this disclosure pertains. Certain terms of art, notations, and other scientific terms or terminology may, however, be defined specifically as indicated below.

The present disclosure provides a meson converter for generating thermal energy from a meson flux, and the use of a meson converter for generating thermal energy from a meson flux. The meson converter may combine regeneration of long-lived neutral kaons, with efficient energy absorption and energy extraction.

1 FIG. 100 100 130 140 130 140 110 130 140 100 120 100 110 100 120 130 schematically illustrates a meson converteraccording to an embodiment of the present disclosure, where the meson convertercomprises plurality of absorber layersand a plurality of heat transport layers. The plurality of absorber layersand the plurality of heat transport layersare here arranged alternatively in a stack, with each absorber layerbeing arranged in contact with at least one heat transport layer. In operation, the meson convertermay be aligned such that a fluxof incoming mesons is incident on the meson collectoron top of the stack. In other words the meson convertermay be aligned such that the meson fluxdirection is aligned in parallel, or at least partly in parallel, with the normal vectors of the absorber layers.

According to the present disclosure, any two adjacent layers in the stack of the meson convertor have dissimilar densities. It has been found that the stacking of such layers with dissimilar densities may induce neutral particle oscillations in a flux of mesons, such as kaons. The stacking of said layers with dissimilar densities may consequently cause regeneration of long-lived neutral kaons, K-long, into short-lived neutral kaons, K-short. K-short decay in 90 picoseconds with 69% probability to pairs of charged pions, and with 31% probability into pairs of neutral pions which then decay to high-energy gamma photons. K-short is thus significantly easier to extract energy from than K-long, which with its relatively long decay time of 52 ns usually pass through most materials with no interaction. When referring to density herein, it will be appreciated that it is referred to density by weight.

Each absorber layer may according to a particular embodiment of the disclosure have a first density, and each transport layer may have a second density being different from the first density. Periodic density fluctuations in the stack has been found to be particularly preferable in order to induce neutral particle oscillations in a flux of mesons, such as kaons.

The absorber layers may according to the present disclosure be configured to absorb radiation, such as radiation in the form of charged particles and/or in the form of electromagnetic radiation. Electromagnetic radiation may here typically comprise radiation in the form of x-rays and gamma rays, and may for example originate as a decay product or as bremsstrahlung. Charged particles may generally be absorbed in the absorber layers as they lose energy by ionization of the material of the absorber layer, or by radiation of bremsstrahlung during the braking in the material of the absorber layer. Electromagnetic radiation, such as x-rays and/or gamma rays, may on the other hand be absorbed by well-known mechanisms such as photoelectric absorption, Compton scattering or pair formation.

The absorber layers in the meson converter may thus generally absorb at least part of the incoming mesons by absorbing charged pions and kaons, and additionally by absorbing the gamma rays originating from neutral pions. Energy from charged pions and kaons may thus be transferred to the absorber for example though absorbance of the bremsstrahlung, while gamma rays from the decay of neutral pions may be absorbed though known mechanisms such as photoelectric absorption, Compton scattering or pair formation.

130 150 100 120 130 130 130 150 130 150 140 110 150 2 FIG. According to an embodiment of the present disclosure, each absorber layermay comprise a metal plate of a first type. Metal plates have been found to be preferable to for example ceramic materials, as metal plates provide adequate absorption properties in combination with good thermal conductivity and thermal expansion properties. As high temperatures may be reached in the meson converterunder influence of a high meson flux, it is preferable that each absorber layerdoes not crack, or otherwise break, due to thermal strain. Metal plates may further contribute to transport heat, thus preventing overheating of the absorber layer.schematically illustrates an embodiment of the present disclosure where each absorber layercomprises a metal plate of a first type. The plurality of absorberlayers in the form of metal plates of a first typeand the plurality of heat transport layersare here arranged in a stack. A metal plate of a first typemay generally herein alternatively be termed a metal plate absorber.

In order to efficiently absorb charged particles and gamma rays, it is preferable that the absorber layers comprise a material with a high atomic number. The latter results in an increased electromagnetic stopping power, and an increased interaction with photons. Metal plates consisting of iron, or at least comprising at least 50 wt. % iron, have been found to be suitable for use as a metal plate of the first type according to the present disclosure. Heavier metals may alternatively constitute the metal plate of the first type, optionally as an alloy. According to a particular embodiment the present disclosure the metal plate of the first type comprises at least 50 wt. % of an element with an atomic number of at least 26.

In a particular embodiment of the present disclosure, the metal plate of the first type comprises at least 50 wt. % lead. Lead may in certain cases be preferred, due to its high atomic number and density. The metal plate of the first type may for example comprise at least 90 wt. % lead, or even at least 99 wt. % lead. Due to the toxic nature of lead, any metal plate of the first type that comprises lead, may according to the present disclosure be coated with a non-toxic material, e.g. a light metal such as aluminium or titanium.

The dimensions of the meson converter may generally vary, but is preferably determined in order to optimize induction of neutral particle oscillations in a flux of mesons, such as kaons. The dimensions of the meson converter may in other words be chosen in order to maximize regeneration of K-long into K-short. As K-short may form at the edge of the meson converter, the thickness of the meson converter, i.e. the thickness/height of the stack, may be chosen to be at least equal to the expected propagation length for K-short. As K-short has an expected half-life of 90 picoseconds and traveling at speeds approaching, but limited by the speed of light, the expected propagation distance for a K-short is then at most approximately 2.7 cm. The thickness of the stack of the meson converter may thus according to the present disclosure be at least 2.7 cm. As the K-shorts continue to decay as they propagate through space, a K-short generated at the entry into the meson converted will with 95% probability have decayed by the time it has travelled at most approximately 11 cm into the meson converter. The exact thickness of the meson converter will be dependent on the exact rate of regeneration, but it has been found that a thickness of the meson converter of approximately 4 times the decay propagation distance, i. e 10.8 cm, is preferable. In a particular embodiment of the present disclosure, the thickness of the meson converter is between 10 cm and 100 cm, more preferably between 10 cm and 50 cm.

The thickness of each absorber layer and each heat transport layer may generally be dependent on the total thickness of the stack. The absorber layers may generally be in the range 1-10 mm, preferably in the range 2-7 mm. The heat transport layers may generally be in the range 1-10 mm, preferably in the range 2-7 mm. In a particular embodiment the thickness of each absorber layer and the thickness of each heat transport layer is 5 mm.

The meson converter comprises according to the present disclosure a plurality of heat transport layers, where each absorber layer is arranged in contact with at least one heat transport layer. The employment of such heat transport layers is preferred in order to prevent the absorber layers from overheating and to keep a uniform temperature in the meson converter. The latter contributes to mitigate thermal strain, and to maintain a more uniform thermal conductivity across the meson converter. Each absorber layer is according to the present disclosure arranged in contact with at least one heat transport layer, but it will be appreciated by a person skilled in the art that each absorber layer may be in contact with two heat transport layers, one on each side. The contact between each absorber layer and one or two heat transport layers is preferable in that each absorption layers may then maintain a desired temperature during operation of the meson converter.

The thermal conductivity of each heat transport layer is preferably higher than the thermal conductivity of any one of the absorber layers. Such a configuration allows the meson converted to be specifically designed with absorber layers specifically adapted to absorbing radiation, and with heat transport layers specifically adapted to transport heat away from the absorber layers. An absorber layer may for example comprise a metal plate of a first type which is particularly suitable for absorbing radiation, but which is not particularly conductive, e.g. iron and lead. In order to effectively transport heat away from the absorber layer, a heat transport layer comprising a metal plate of a second type may be employed. The metal plate of the second type may have higher thermal conductivity than the metal plate of the first type. The metal plate of the second type may for example comprise aluminium. In a particular embodiment of the present disclosure, the metal plate of the second type has a thermal conductivity of at least 200 W/m·K. A metal plate of the second type having said thermal conductivity has been found to be particularly suitable for obtaining effective heat transport in the meson converter. Examples of materials that may be used in the metal plate of the second type include aluminium, gold, copper or silver. The metal plate of the second type may thus comprise aluminium, gold, copper or silver, for example at a quantity of at least 50 wt. %, or more preferable at a quantity of at least 95 wt. %. The thermal conductivity of any one heat transport layer is in a particular embodiment higher than the thermal conductivity of any one of its adjacent absorber layers, at least any one of its adjacent absorber layers being in contact with the heat transport layer.

2 FIG. 100 140 160 130 150 140 160 130 150 160 110 160 schematically illustrates a meson converteraccording to the present disclosure where each heat transport layercomprises a metal plate of a second type. The absorption layersare here illustrated, optionally as a metal plate of a first type, where each absorber layers is in direct contact with two heat transport layersin the form of metals plates of the second type, one on each side. The plurality of absorber layers, optionally in the form of metal plates of a first type, and the plurality of metal plates of the second typeare here arranged in a stack. A metal plate of a second typemay generally herein alternatively be termed a metal heat transport plate.

3 FIG. 4 FIG. 100 140 165 165 165 130 130 165 165 166 100 100 210 100 schematically illustrates a meson converteraccording to an embodiment of the disclosure where each heat transport layercomprises a conduitconfigured to conduct a cooling fluid, preferably water. Said conduitmay thus be employed as a conduitfor a flow of cooling fluid which may actively cool the absorption layers. Despite most fluids, including water, having a relatively low intrinsic thermal conductivity, effective thermal control of the absorption layersmay be obtained by controlling the flow and temperature of the cooling fluid. The cooling fluid may further be utilized, directly or indirectly for the purpose of generating electrical power. The cooling fluid may for example be used in order to generate steam, which further may be used in order to drive an electrical turbine, not shown. Each conduit, may for example be a void between each absorber layer. The conduitsmay as schematically illustrated inbe connected to a fluid source, such as a main conduit, so that the cooling fluid may be circulated though the meson converter. The meson convertermay further generally comprise a frame, or any similar support structure configured to support the various components of the meson converter.

140 160 140 100 100 180 180 110 140 180 140 168 180 168 180 180 168 5 FIG. It will be appreciated by a person skilled in the art that a general cooling system may be combined with other embodiments of the present disclosure, for example the embodiment where each heat transport layercomprises a metal plate of a second type. In the latter embodiment a cooling fluid system may be employed in order to cool each heat transport layer, for example in a particular separate part of the meson converter.schematically illustrates a particular embodiment of the present disclosure where the meson converterfurther comprises a chamberfor containing and conducting water. The chambermay be connected to one side of the stack, and may for example be connected directly or indirectly to the heat transport layers. The chambermay for example be connected to the heat transport layersvia one or more heat conductors, such as metallic conductors, or the heat transport layers may as an alternative extend into the chamber. The one or more heat conductorsmay for example be in contact with the chamberin order to enable cooling water flowing through said chamberto cool the one or more heat conductors.

100 120 100 100 130 140 100 100 6 FIG. A meson convertermay generally be employed in order to absorb energy from nuclear reactions, such as fusion reaction at a small or medium scale. As many nuclear reactions typically are occurring in a limited spatial volume, the meson fluxthat is generated in such processes may propagate with a semi-spherical distribution from their source of origin. A meson converteremployed in order to convert and absorb mesons from a nuclear reaction may therefore be designed to curve around said source of origin for a meson flux. The meson convertermay thus, as schematically illustrated inbe curved. The absorber layersand the heat transport layersof the meson converter may thus consequently be curved. Alternatively the meson convertermay be planar, for example such that several meson converters may be assembled into a suitable shape. It will be appreciated by a person skilled in the art that the various shapes of the meson converted herein described, e.g. the embodiment where the meson converteris curved, may be combined with any embodiment of the present disclosure.

100 210 130 140 100 130 150 210 150 150 140 160 160 160 150 160 100 210 4 5 FIGS.and The meson convertermay generally comprise additional parts such as a frame, fastening means for mounting any absorption layersand or heat transport layers, water cooling equipment, such as valves, conduits, flanges etc. The actual assembly of a meson converteraccording to the description herein may, as will be appreciated by a person skilled in the art, be performed in a variety of ways. Absorption layersin the form of metal plates of a first typemay for example be mounted in an external framethat is attached to the metal plates of the first typealong the planar edge of the metal plates of the first type. Heat transport layersin the form of metal plates of a second typemay for example be mounted in the external frame that is attached to the metal plates of the second typealong the planar edge of the metal plates of the second type. Metal plates of a first typeand metal plates of a second typemay further be brought in contact with each other using a wide variety of techniques. The metal plates may for example be bonded together using high temperature bonding where the metals plates are heated to a temperature where one type of plate softens and conforms to its adjacent plates.schematically illustrate a meson convertercomprising a frame.

A second aspect of the present disclosure provides use of a meson converter for generating thermal energy from a meson flux. The meson flux may comprise a kaon flux.